Transcriptomic Insights Into the Evolution of Snake Venom: Mechanisms, Diversity, and Adaptation

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  Transcriptomic Insights Into the Evolution of Snake Venom: Mechanisms, Diversity, and Adaptation Abstract Snake venoms are evolutionarily refined biochemical arsenals composed of diverse toxins with complex functional roles in predation, defense, and competition. Over the past 2 decades, transcriptomic approaches have transformed venom research by enabling high-resolution insights into gene expression dynamics, molecular diversity, and the evolutionary mechanisms driving venom variation across lineages. In this review, we present a comprehensive synthesis of snake venom transcriptomics literature and propose a conceptual framework structured around three major axes: (1) gene family expansion through duplication and neofunctionalization; (2) regulatory complexity encompassing transcriptional, posttranscriptional, and epigenetic modulation; and (3) ecological selection pressures shaping venom profiles in response to diet, habitat, and interspecific interactions. We integrate findin...

From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report

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From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report

Abstract

Background

Scorpion envenomation is a significant medical concern in tropical and subtropical regions, with cardiovascular complications being among its most severe manifestations. While scorpion venom-induced cardiac dysfunction is well-documented, complete atrioventricular (AV) block is a rare occurrence. This case highlights a unique presentation of complete heart block following a yellow scorpion sting, emphasizing the importance of early recognition and management.

Case presentation

A 56-year-old Middle Eastern (Iranian) male presented to the emergency department with dizziness, syncope, and severe bradycardia following a yellow scorpion sting. Electrocardiographic evaluation revealed a complete atrioventricular block. Laboratory findings indicated elevated cardiac biomarkers, suggesting myocardial injury. Echocardiography demonstrated left ventricular dysfunction without significant structural abnormalities. The patient required temporary transvenous pacing for hemodynamic stabilization and was managed with supportive care, including intravenous fluids, atropine, and continuous cardiac monitoring. Over the course of hospitalization, his conduction abnormality resolved by permanent pacemaker, and he was discharged in stable condition.

Conclusions

This case underscores the potential for severe cardiac complications following scorpion envenomation, particularly conduction disturbances such as complete atrioventricular block. Although rare, healthcare providers should be aware of this life-threatening consequence and initiate prompt intervention to prevent adverse outcomes. Increased awareness and timely management can significantly improve prognosis in affected patients.

Zibaeenezhad, M.J., Alizadeh, Z., Rajabi, A. et al. From sting to pacemaker: a case of complete heart block following yellow scorpion envenomation—a case report. J Med Case Reports 19, 620 (2025). https://doi.org/10.1186/s13256-025-05687-0